Whatâ??s the business purpose? You might be surprised what the business will and will not tolerate related to this ...

Although it doesnâ??t strictly itself prevent concurrent sessions, Iâ??ve seen people use a two factor system to discourage it for common use cases. (Like people in different locations canâ??t easily get SMS based pins)

Matt Konda

> On Nov 19, 2014, at 4:30 AM, Robin Wood <robin (at) digi (dot) ninj [email concealed]a> wrote:
>
> What are peoples opinions on allowing concurrent logins to web apps? I
> suppose it depends on what the app is used for - forum, admin suite
> etc - but do the protections from it add more problems that allowing
> it?
>
> Solutions I can see are:
>
> 1. Allow concurrent logins
> 2. Allow concurrent logins but report that someone else is logged it -
> like Gmail does
> 3. Don't allow them and kick out any logged in user when a new one logs in
> 4. Don't allow them and lock out all new logins till old ones have logged out
> 5. Give a warning popup when logging in to say the account is in use
> elsewhere as well
> 6. Allow but report back to an admin or log tracker or similar
>
> 1 is the default in most cases.
> 2 is a good idea but really, how many people look at the little thing
> in Gmail which says where else the account is logged in from, I don't
> and I'm sure normal users don't even know it exists.
> 3. Good but if an attacker gets creds or a reliable session hijack
> then they can use them to DoS legit users by keep logging them out.
> 4. Good but if an attacker gets in they can keep the account active
> and so DoS the real user by never letting them log in.
> 5. Maybe the best option but only works in the legit user logs in
> second otherwise the attacker gets the warning and ignores it.
> 6. Good one if people are watching the logs and can act on them.
>
> What other options are there? Can it be done in a good way that makes
> if of any use?
>
> Robin
>
>
>
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